(1-1/2)x(1+1/2)x(1-1/3)x(1+1/3)x.x(1-1/99)x(1+1/99)结果是等于50/99吗我算出来了就是不能确定
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(1-1/2)x(1+1/2)x(1-1/3)x(1+1/3)x.x(1-1/99)x(1+1/99)结果是等于50/99吗我算出来了就是不能确定
(1-1/2)x(1+1/2)x(1-1/3)x(1+1/3)x.x(1-1/99)x(1+1/99)结果是等于50/99吗我算出来了就是不能确定
(1-1/2)x(1+1/2)x(1-1/3)x(1+1/3)x.x(1-1/99)x(1+1/99)结果是等于50/99吗我算出来了就是不能确定
如果自己接受不了,可就先别算那么长,一节节算算,找找规律
(1-1/2) X (1+1/2) X (1-1/3) X (1+1/3)
= 1/2 X 3/2 X 2/3 X 4/3
= 1/2 X 1 X 4/3
= 2/3
(1-1/2) X (1+1/2) X (1-1/3) X (1+1/3) X (1-1/4) X (1+1/4)
= 1/2 X 3/2 X 2/3 X 4/3 X 3/4 X 5/4
= 1/2 X 1 X 1 X 5/4
= 5/8
同理,题目就是
(1-1/2) X (1+1/2) X (1-1/3) X …… X (1+1/98) X (1-1/99) X (1+1/99)
= 1/2 X 3/2 X 2/3 X …… X 99/98 X 98/99 X 100/99
= 1/2 X 1 X 1 X …… X 1 X 100/99
= 50/99
(1-1/2)x(1+1/2)x(1-1/3)x(1+1/3)x......x(1-1/99)x(1+1/99)
=1/2x3/2x2/3x3/4x4/3x....x98/99x100/99
=1/2x1x1x....x1x100/99
=50/99
对的啊你和我想的是一样的,就是中间你顺序好像写反了···没有 就是这样做的。中间的2项相乘=1 就剩下第一项和最后一...
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(1-1/2)x(1+1/2)x(1-1/3)x(1+1/3)x......x(1-1/99)x(1+1/99)
=1/2x3/2x2/3x3/4x4/3x....x98/99x100/99
=1/2x1x1x....x1x100/99
=50/99
对的
收起
(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*......*(1+1/99)(1-1/99)
=(1+1/2)(1+1/3)...(1+1/99)(1-1/2)(1-1/3)...(1-1/99)
=[3/2*4/3...100/99]*[1/2*2/3...98/99]
=100/2*1/99
=50/99